This invention relates to a system for acquiring fingerprints and other characteristic patterns and, more specifically, to a system utilizing a fiberoptic block to detect and transmit a characteristic pattern image for analysis.
Several fingerprint acquisition systems have been reported in the art.
U.S. Pat. No. 3,668,633 to Sadowsky discloses the use of separate arrays of optical fibers for transmitting light to a finger and for receiving a fingerprint reflection.
U.S. Pat. No. 4,582,985 to Lofberg discloses the use of an array of sensing elements to detect a fingerprint. Each sensing element is attached to a single optical fiber which carries light from an LED to a finger and which also carries the light reflected from the fingerprint back to a phototransistor which then processes the fingerprint image electronically. The finger is disclosed as being spaced from the fiber end which is shown as having an end face slightly curved but generally perpendicular to its axis.
A number of other patents disclose the use of transparent blocks upon which a finger is placed and through which a detecting light signal is internally reflected at less than the critical angle with respect to the block surface. The internally reflected light signal carries the image of the fingerprint as a result of selective light absorption at the fingerprint ridges. These patents are U.S. Pat. Nos. 4,120,535 to De Palma et al, 4,553,837 to Marcus, 4,210,899 to Swonger et al, 4,537,484 to Fowler et al, 4,032,889 to Nassimbene, and 4,553,267 and 4,322,163, both to Schiller.
These prior art fingerprint acquisition systems in general utilize complex, costly and fragile components, especially those adapted for detecting the fingerprint itself. In addition, these systems do not always offer the high resolution and detail required for high accuracy fingerprint definition. Because of such problems, these conventional systems are typically not suited for widespread use and are generally confined to a narrow range of applications which justify complexity and expense.
Bearing in mind these and other deficiencies of the prior art, it is an object of the present invention to provide a means for acquiring fingerprints and other characteristic patterns which offers considerable simplicity in design and construction.
It is another object of the present invention to provide a fingerprint acquisition system which has high resolution capability.
It is a further object of the present invention to provide a fingerprint acquisition system which is intended for widespread security and identification applications.
It is another object of the present invention to provide a means for acquiring fingerprints and other characteristic patterns which has high durability in repeated use.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
A better understanding of the objects, advantages, features, properties and relations of the invention will be obtained from the following detailed description and accompanying drawings which set forth an illustrative embodiment and is indicative of the way in which the principle of the invention is employed.